In the bottling industry, economic and environmental concerns are a constant incentive behind the manufacture of closure and liner systems that are inexpensive and as environmentally correct as possible. Both closures and liners are being made thinner, which results in problems that were not a concern with previously available closure and liner systems. Particularly, when using thinner structures, the compressibility that thicker materials offer is lost and, consequently, a greater percentage of non-seals result. The molding processes and the particular plastics used to form containers are rarely consistent and irregularities on the land of the container can be common. Therefore, thinner, less compressible liners and irregularities on the container land may prevent a proper, total seal of the liner to the container land.
If the seal between a given liner and the container land is inadequate, the container contents may spoil, lose its freshness and become unmarketable. Further, because a properly sealed liner generally performs a tamper-indicating function, an improper seal may be viewed by the consumer as an attempt at container tampering.
Therefore, there is a need for a closure which incorporates a structure that will compensate for the use of a thin liner and closure construction and irregularities on the container land. The closure should provide wrap-around liner contact with the container land. The closure must perform this task without increased expense and without raising environmental concerns that the thinner closures and liners are designed to solve.